This invention relates to aircraft tugs, and more particularly to a novel method and apparatus for attaching an aircraft tug to the nosewheel tire of an airplane.
An aircraft tug is a machine used to move an airplane about a runway without the assistance of the airplane's engines. A standard aircraft tug, such as the Ingersoll-Rand "Paymover" tractor, attaches to an airplane via a towing bar that is connected to the airplane's nosewheel assembly at one end of the towing bar and to the tug at the other end of the towing bar as shown in FIG. 1. The connection at the tug end of the towing bar is usually a universal joint, so as to allow for convenient maneuvering of the airplane by the tug. The connection between the towing bar and the airplane is normally a firm connection to the axle of the nosewheel of the airplane, so that the nosewheel rotates in conjunction with lateral movement of the towing bar. With this standard tug arrangement, the traction necessary to tow the airplane must be supplied entirely by the weight of the tug itself. Conventional tugs, used to maneuver large airplanes such as a Boeing 747 Jetliner, must therefore weigh in excess of twenty-five tons to have adequate traction to function properly.
A newer approach for overcoming the problem of excessive tug weight has been developed by Air Traction Industries, Ltd. of England and described in the article entitled "An Aircraft Tug Which Revolutionizes Ground Handling" which appeared in Aircraft Engineering, page 21, June, 1985. The tug described therein is designated by the company as its ASSET.TM. tug.
The ASSET tug includes a lifting system which locates on the nosewheel jacking point and provides for lifting the nosewheel and tire assembly onto a turntable where it is then firmly secured. This system allows the nosewheel to remain in a locked position during relocation of the airplane by the ASSET tug. The ASSET tug has the disadvantage of requiring specialized adapters for different airplane makes and models. These adapters take time, effort, and manpower to install for each use of the tug, and are prone to being misplaced or lost.
To the best knowledge and belief of the inventors of the instant invention, there are no methods or apparatus disclosed in the aircraft tug prior art which include a capability for capturing, lifting, and maneuvering an airplane by its nosewheel and tire assembly without specialized adapters for different types of airplanes.
It is therefore an object of this invention to provide a universal method and apparatus for attaching an aircraft tug to the front wheel and tire assembly of an airplane in a way that allows the tug to use part of the weight of the airplane for traction purposes without any need for specialized adapters for various airplanes.
It is another object of this invention to make the attachment process for connecting an aircraft tug to an airplane a relatively simple, efficient, one-person operation that is both economical and safe.
It is yet another object of this invention to provide an aircraft tug with an adjustable airplane tire capturing and lifting apparatus that is capable of accomodating airplane nosewheel and tire assemblies of widely different size and shape.
These and other objects of the invention will become clear to the reader upon careful perusal of the following summary and descriptions.